Needle catheters are often employed to inject fluids and/or obtain fluid or tissue samples for diagnosis and/or treatment. In these procedures, a needle is advanced to a target tissue site within a catheter under ultrasound guidance. The needle may be advanced distally from the catheter to penetrate the target site. The ultrasound image can allow a user to visualize the position of the needle in relation to the target and surrounding structures and aids in ensuring that a correct tissue portion is treated, sampled, etc. to minimize the risk of trauma or injury to non-targeted tissue. A common challenge associated with the use of ultrasound imaging is the relatively low echogenicity of the needle and the lack of clarity in the resulting images.
As would be understood by those skilled in the art, several factors play a role in the echogenicity of the needle including needle gauge, the difference in acoustic impedance between the needle and the surrounding tissue, the angle of the needle relative to the transducer, the frequency being used and various characteristics of the processing algorithm.